期刊文献+
共找到594篇文章
< 1 2 30 >
每页显示 20 50 100
Real pairwise completely positive matrices
1
作者 ZHOU Anwa HE Jiayi 《运筹学学报(中英文)》 北大核心 2025年第3期160-178,共19页
In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise c... In this paper,we introduce the real pairwise completely positive(RPCP)matrices with one of them is necessarily positive semidefinite while the other one is necessarily entrywise nonnegative,which has a real pairwise completely positive(RPCP)decomposition.We study the properties of RPCP matrices and give some necessary and sufficient conditions for a matrix pair to be RPCP.First,we give an equivalent decomposition for the RPCP matrices,which is different from the RPCP-decomposition and show that the matrix pair(X,X)is RPCP if and only if X is completely positive.Besides,we also prove that the RPCP matrices checking problem is equivalent to the separable completion problem.A semidefinite algorithm is also proposed for detecting whether or not a matrix pair is RPCP.The asymptotic and finite convergence of the algorithm are also discussed.If it is RPCP,we can further give a RPCP-decomposition for it;if it is not,we can obtain a certificate for this. 展开更多
关键词 real pairwise completely positive matrices truncated moment problem semidefinite relaxation
在线阅读 下载PDF
DPBD——设计一类强NP-Complete问题近似算法的有效方法
2
作者 鄢勇 金灿明 《电子学报》 EI CAS CSCD 北大核心 1992年第11期63-68,共6页
本文针对一类强NP-Complete问题近似算法的设计问题,提出一种通用的设计策略DPBD,它通过一局部近似算法而获得一全局近似算法,并保证精度在一定范围内.最后,本文将DPBD应用于一著名的NP难度问题:平面Covering问题,对方法的有效性给予了... 本文针对一类强NP-Complete问题近似算法的设计问题,提出一种通用的设计策略DPBD,它通过一局部近似算法而获得一全局近似算法,并保证精度在一定范围内.最后,本文将DPBD应用于一著名的NP难度问题:平面Covering问题,对方法的有效性给予了证实. 展开更多
关键词 计算机 算法 DPBD方法
在线阅读 下载PDF
On the completeness of eigen and root vector systems for fourth-order operator matrices and their applications 被引量:1
3
作者 王华 阿拉坦仓 黄俊杰 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第10期8-14,共7页
In this paper, we consider the eigenvalue problem of a class of fourth-order operator matrices appearing in mechan- ics, including the geometric multiplicity, algebraic index, and algebraic multiplicity of the eigenva... In this paper, we consider the eigenvalue problem of a class of fourth-order operator matrices appearing in mechan- ics, including the geometric multiplicity, algebraic index, and algebraic multiplicity of the eigenvalue, the symplectic orthogonality, and completeness of eigen and root vector systems. The obtained results are applied to the plate bending problem. 展开更多
关键词 operator matrix eigenvalue problem EIGENVECTOR root vector completeNESS
原文传递
Maps Completely Preserving Jordan 1-*-Zero-Product on Factor Von Neumann Algebras 被引量:1
4
作者 Li HUANG Yu ZHANG Wenhui LI 《Journal of Mathematical Research with Applications》 CSCD 2018年第3期287-292,共6页
Let H, K be infinite dimensional complex Hilbert spaces, and A, B be factor von Neumann algebras on H and K, respectively. It is shown that every surjective map completely preserving Jordan 1-*-zero-product from A to... Let H, K be infinite dimensional complex Hilbert spaces, and A, B be factor von Neumann algebras on H and K, respectively. It is shown that every surjective map completely preserving Jordan 1-*-zero-product from A to B is a nonzero scalar multiple of either a linear*-isomorphism or a conjugate linear *-isomorphism. 展开更多
关键词 factor von Neumann algebras Jordan 1-zero-product complete preserver problems
原文传递
TOEPLITZ AND POSITIVE SEMIDEFINITE COMPLETION PROBLEM FOR CYCLE GRAPH 被引量:1
5
作者 何明 吴国宝 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2005年第1期67-78,共12页
We present a sufficient and necessary condition for a so-called Cnk pattern to have positive semidefnite (PSD) completion. Since the graph of the Cnk pattern is composed by some simple cycles, our results extend those... We present a sufficient and necessary condition for a so-called Cnk pattern to have positive semidefnite (PSD) completion. Since the graph of the Cnk pattern is composed by some simple cycles, our results extend those given in [1] for a simple cycle.We also derive some results for a partial Toeplitz PSD matrix specifying the Cnk pattern to have PSD completion and Toeplitz PSD completion. 展开更多
关键词 循环图表 矩阵 Cn^K模式 计算方法
在线阅读 下载PDF
Ring Isomorphisms and Complete Preservers of Fixed Points for Multipliers
6
作者 Ting ZHANG Jinchuan HOU 《Journal of Mathematical Research with Applications》 CSCD 2019年第1期89-100,共12页
Let R_1 and R_2 be two rings with unit I. We give some characterizations of ring homomorphisms and ring isomorphisms between R_1 and R_2 in term of complete preservers of fixed points of multipliers, under some mild a... Let R_1 and R_2 be two rings with unit I. We give some characterizations of ring homomorphisms and ring isomorphisms between R_1 and R_2 in term of complete preservers of fixed points of multipliers, under some mild assumption on R_1. Applications to several kinds of operator algebras such as Banach algebras, nest algebras, matrix algebras and standard operator algebras are presented. 展开更多
关键词 complete PRESERVER problem BANACH algebra RING isomorphism operator on BANACH space
原文传递
A Finite-Dimensional Completely Integrable System Associated with Boussinesq Hierarchy
7
作者 CHEN Lan-Xin ZHANG Jun-Xian 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第12期1081-1086,共6页
In this paper, a new completely integrable system related to the complex spectral problem -φ xx+(i/4)wpx+(i/4)(wp)x+(1/4)vφ=iλφxand the constrained flows of the Boussinesq equations axe generated. Accor... In this paper, a new completely integrable system related to the complex spectral problem -φ xx+(i/4)wpx+(i/4)(wp)x+(1/4)vφ=iλφxand the constrained flows of the Boussinesq equations axe generated. According to the viewpoint of Hamiltonian mechanics, the Euler-Lagrange equations and the Legendre transformations, a reasonable Jacobi-Ostrogradsky coordinate system is obtained. Moreover, by means of the constrained conditions between the potentiaJ u, v and the eigenfunction φ, the involutive representations of the solutions for the Boussinesq equation hieraxchy axe given. 展开更多
关键词 eigenvalue problem constraint flow symplectic manifold completely integrability involutive representation
在线阅读 下载PDF
Nonlinear Electrical Impedance Tomography Method Using a Complete Electrode Model for the Characterization of Heterogeneous Domains
8
作者 Jeongwoo Park Bong-Gu Jung Jun Won Kang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第3期1707-1735,共29页
This paper presents an electrical impedance tomography(EIT)method using a partial-differential-equationconstrained optimization approach.The forward problem in the inversion framework is described by a complete electr... This paper presents an electrical impedance tomography(EIT)method using a partial-differential-equationconstrained optimization approach.The forward problem in the inversion framework is described by a complete electrodemodel(CEM),which seeks the electric potential within the domain and at surface electrodes considering the contact impedance between them.The finite element solution of the electric potential has been validated using a commercial code.The inverse medium problem for reconstructing the unknown electrical conductivity profile is formulated as an optimization problem constrained by the CEM.The method seeks the optimal solution of the domain’s electrical conductivity to minimize a Lagrangian functional consisting of a least-squares objective functional and a regularization term.Enforcing the stationarity of the Lagrangian leads to state,adjoint,and control problems,which constitute the Karush-Kuhn-Tucker(KKT)first-order optimality conditions.Subsequently,the electrical conductivity profile of the domain is iteratively updated by solving the KKT conditions in the reduced space of the control variable.Numerical results show that the relative error of the measured and calculated electric potentials after the inversion is less than 1%,demonstrating the successful reconstruction of heterogeneous electrical conductivity profiles using the proposed EIT method.This method thus represents an application framework for nondestructive evaluation of structures and geotechnical site characterization. 展开更多
关键词 Electrical impedance tomography complete electrode model inverse medium problem Karush-Kuhn-Tucker(KKT)optimality conditions nondestructive evaluation of structures
在线阅读 下载PDF
Equipment delivery and quality problems affectingcompletion of 1997 Power Construction Plan
9
《Electricity》 1998年第2期43-44,共2页
关键词 Equipment delivery and quality problems affecting completion of 1997 Power Construction Plan
在线阅读 下载PDF
The Totally Non-positive Matrix Completion Problem
10
作者 Jun-ping Liang Ming He 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2006年第4期312-319,共8页
In this paper, the totally non-positive matrix is introduced. The totally non-positive completion asks which partial totally non-positive matrices have a completion to a totally non-positive matrix. This problem has. ... In this paper, the totally non-positive matrix is introduced. The totally non-positive completion asks which partial totally non-positive matrices have a completion to a totally non-positive matrix. This problem has. in general, a negative answer. Therefore, our question is for what kind of labeled graphs G each partial totally non-positive matrix whose associated graph is G has a totally non-positive completion? If G is not a monotonically labeled graph or monotonically labeled cycle, we give necessary and sufficient conditions that guarantee the existence of the desired completion. 展开更多
关键词 完备化问题 完全非正矩阵 计算数学 否定回答
在线阅读 下载PDF
Common Problems and Countermeasures of the Completion Settlement Audit of Construction Projects
11
作者 YAOWen 《外文科技期刊数据库(文摘版)经济管理》 2022年第8期041-044,共4页
The rapid development of the construction industry has effectively increased the scale of construction engineering and enriched the types of construction projects. In order to promote the development of the constructi... The rapid development of the construction industry has effectively increased the scale of construction engineering and enriched the types of construction projects. In order to promote the development of the construction industry towards a more standardized and professional direction, it is also necessary to do a good job of the overall control of construction costs, in order to improve the overall economic benefits of enterprises. Among them, the most important link is the project completion settlement audit, through the project audit, can intuitively understand the cost information in the process of project construction, fully grasp the dynamic use of funds, to avoid the waste of resources. However, the work of project completion settlement audit is generally more complex, and involves many process links, leading to many problems in the actual work. Therefore, in the follow-up work, we should pay attention to the professionalism and rationality of the project completion settlement audit work, so as to significantly improve the overall level of the construction project completion settlement audit. 展开更多
关键词 construction project completion settlement audit problemS COUNTERMEASURES
原文传递
Nonlocal controllability for semilinear problems in Banach spaces
12
作者 薛星美 吕忠 《Journal of Southeast University(English Edition)》 EI CAS 2008年第4期541-544,共4页
If A: D(A) X→X is a densely defined and closed linear operator, which generates a linear semigroup S (t) in Banach space X. The nonlocal control/ability for the following nonlocal semilinear problems: u' (t... If A: D(A) X→X is a densely defined and closed linear operator, which generates a linear semigroup S (t) in Banach space X. The nonlocal control/ability for the following nonlocal semilinear problems: u' (t) = Au (t) + Bx( t) + f( t, u(t) ), 0≤t ≤ T with nonlocal initial condition u(0) = u0 + g(u) is discussed in Banach space X. The results show that if semigroup S(t) is strongly continuous, the functionsf and g are compact and the control B is bounded, then it is nonlocally controllable. The nonlocal controllability for the above nonlocal problem is also studied when B and W are unbounded and the semigroup S(t) is compact or strongly continuous. For illustration, a partial differential equation is worked out. 展开更多
关键词 nonlocal problem nonlocal controllability mild solution completely continuous
在线阅读 下载PDF
The Improved Interpolating Complex Variable Element-Free Galerkin Met hod for Two- D imensional Elastic Problems 被引量:1
13
作者 Yajie Deng Ying Dai 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2022年第2期328-343,共16页
An improved interpolating complex variable element-frees Galerkin(IICVEFG)method for the two-dimensional elastic problems is developed.This method is based on the improved interpolating complex variable moving least-s... An improved interpolating complex variable element-frees Galerkin(IICVEFG)method for the two-dimensional elastic problems is developed.This method is based on the improved interpolating complex variable moving least-squares(IICVMLS)method and the integral form of the elastic problems.In the IICVEFG method,the proposed shape function has the interpolating feature.Therefore,the essential boundary conditions can be exerted directly.Additionally,the unnecessary t erms in the discrete mat rices are removed,which resul ts in a set of concise formulas.This method is verified by analyzing three elastic examples under different constraints and loads.The numerical results show that the IICVEFG method is superior in precision and efficiency to other non-interpolating meshless methods. 展开更多
关键词 Interpolating meshless met hod Elastic problems Singular weight function complete basis function
原文传递
Parallel discrete lion swarm optimization algorithm for solving traveling salesman problem 被引量:4
14
作者 ZHANG Daoqing JIANG Mingyan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第4期751-760,共10页
As a typical representative of the NP-complete problem, the traveling salesman problem(TSP) is widely utilized in computer networks, logistics distribution, and other fields. In this paper, a discrete lion swarm optim... As a typical representative of the NP-complete problem, the traveling salesman problem(TSP) is widely utilized in computer networks, logistics distribution, and other fields. In this paper, a discrete lion swarm optimization(DLSO) algorithm is proposed to solve the TSP. Firstly, we introduce discrete coding and order crossover operators in DLSO. Secondly, we use the complete 2-opt(C2-opt) algorithm to enhance the local search ability.Then in order to enhance the efficiency of the algorithm, a parallel discrete lion swarm optimization(PDLSO) algorithm is proposed.The PDLSO has multiple populations, and each sub-population independently runs the DLSO algorithm in parallel. We use the ring topology to transfer information between sub-populations. Experiments on some benchmarks TSP problems show that the DLSO algorithm has a better accuracy than other algorithms, and the PDLSO algorithm can effectively shorten the running time. 展开更多
关键词 discrete lion swarm optimization(DLSO)algorithm complete 2-opt(C2-opt)algorithm parallel discrete lion swarm optimization(PDLSO)algorithm traveling salesman problem(TSP)
在线阅读 下载PDF
ON SPECTRAL PROBLEM FOR VISCOUS SHEAR FLOWS
15
作者 B. S. NG W. H. REID Department of Mathematical Sciences, Indiana University Purdue University Indianapolis, Indiana 46202 3216 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2001年第z1期93-95,共3页
An important aspect of the Orr Sommerfeld problem, which governs the linear stability of parallel shear flows, is concerned with the study of the temporal and spatial spectra for large but finite values of the Reynold... An important aspect of the Orr Sommerfeld problem, which governs the linear stability of parallel shear flows, is concerned with the study of the temporal and spatial spectra for large but finite values of the Reynolds number R . By using only outer (WKB) approximations which are valid in the "complete" sense, we are able to derive approximations to the eigenvalue relation for channel flows, pipe flow, and boundary layer flows which are all remarkably simple and which have a relative error of order ( αR) -1/2 . In this paper, we discuss briefly the basic ideas involved in the derivation of these approximations for boundary layer flows. We then present some results to illustrate the effectiveness of these new approximations. For example, we are even able to compute eigenvalues which lie arbitrarily close to the continuous spectra where all previous numerical treatments have failed. 展开更多
关键词 Orr-Sommerfeld problem HYDRODYNAMICS stability EIGENVALUE problem complete ASYMPTOTIC approximation
在线阅读 下载PDF
Fast Algorithm for the Travelling Salesman Problem and the Proof of P = NP 被引量:1
16
作者 Jinliang Wang 《Applied Mathematics》 2018年第12期1351-1359,共9页
In the theory of computational complexity, the travelling salesman problem is a typical one in the NP class. With the aid of a brand-new approach named “maximum-deleting method”, a fast algorithm is constructed for ... In the theory of computational complexity, the travelling salesman problem is a typical one in the NP class. With the aid of a brand-new approach named “maximum-deleting method”, a fast algorithm is constructed for it with a polynomial time of biquadrate, which greatly reduces the computational complexity. Since this problem is also NP-complete, as a corollary, P = NP is proved to be true. It indicates the crack of the well-known open problem named “P versus NP”. 展开更多
关键词 TRAVELLING SALESMAN problem P versus NP problem NP-complete Computational Complexity Maximum-Deleting Method
在线阅读 下载PDF
EXISTENCE THEOREMS OF SOLUTIONS FOR TWO-POINT BOUNDARY VALUE PROBLEM OF SECOND ORDER ORDINARY DIFFERENTIAL EQUATIONS IN BANACH SPACES
17
作者 张石生 王凡 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1996年第2期99-108,共10页
By using partial order method. some existing theorems of solutions for two-point bouniary value problem of second order ordinary differenlial equations in Banach spaces are given.
关键词 two-point boundary value problem weakly sequentially complete Banach space normal cone
在线阅读 下载PDF
Solving the independent set problem by sticker based DNA computers
18
作者 Hassan Taghipour Ahad Taghipour +1 位作者 Mahdi Rezaei Heydar Ali Esmaili 《American Journal of Molecular Biology》 2012年第2期153-158,共6页
In this paper, the sticker based DNA computing was used for solving the independent set problem. At first, solution space was constructed by using appropriate DNA memory complexes. We defined a new operation called “... In this paper, the sticker based DNA computing was used for solving the independent set problem. At first, solution space was constructed by using appropriate DNA memory complexes. We defined a new operation called “divide” and applied it in construction of solution space. Then, by application of a sticker based parallel algorithm using biological operations, independent set problem was resolved in polynomial time. 展开更多
关键词 Parallel Computing Sticker BASED DNA COMPUTERS INDEPENDENT Set problem NP-complete problem
在线阅读 下载PDF
Applying Surface-Based DNA Computing for Solving the Dominating Set Problem
19
作者 Hassan Taghipour Mahdi Rezaei Heydar Ali Esmaili 《American Journal of Molecular Biology》 2012年第3期286-290,共5页
The surface-based DNA computing is one of the methods of DNA computing which uses DNA strands immobilized on a solid surface. In this paper, we applied surface-based DNA computing for solving the dominating set proble... The surface-based DNA computing is one of the methods of DNA computing which uses DNA strands immobilized on a solid surface. In this paper, we applied surface-based DNA computing for solving the dominating set problem. At first step, surface-based DNA solution space was constructed by using appropriate DNA strands. Then, by application of a DNA parallel algorithm, dominating set problem was resolved in polynomial time. 展开更多
关键词 Parallel Computing Surface-Based DNA Computers Dominating Set problem NP-complete problem
在线阅读 下载PDF
Solving a Traveling Salesman Problem with a Flower Structure
20
作者 Gabriele Martino 《Journal of Applied Mathematics and Physics》 2014年第7期718-722,共5页
This works aims to give an answer to the problem P = NP? The result is positive with the criteria that solve the Traveling Salesman Problem in polynomial cost of the input size and a proof is given. This problem gets ... This works aims to give an answer to the problem P = NP? The result is positive with the criteria that solve the Traveling Salesman Problem in polynomial cost of the input size and a proof is given. This problem gets a solution because a polyhedron, with a cut flower looking, is introduced instead of graph (e.g. tree). 展开更多
关键词 TRAVELING SALESMAN problem POLYHEDRON FLOWER NP-complete
在线阅读 下载PDF
上一页 1 2 30 下一页 到第
使用帮助 返回顶部